Electronic components such as radios, receivers, amplifiers, tape and disk drives, tape transport mechanisms, and other electronic peripherals are commonly housed in low profile rectangular-shape chassis which are mounted directly to vertical rack rails contained in a rack case. The front panel of the chassis serves as a control panel for the electronic circuity contained therein and supports entirely the weight of the chassis and component contained therein by direct attachment to the vertical rack rails.
Such electronic component chassis are typically stack mounted upon rack rails positioned near the open front of a box-like rack case. The body of the chassis is inserted into the interior of the rack case so that laterally extending tabs of the front mounting panel of the chassis come in direct contact with a front face of the rack rails. In this manner, multiple electronic components may be vertically mounted one on top another upon common rack rails within a rack case without the need for any additional support of the chassis other than at the point of attachment of each chassis front panel to the rack rails.
Several problems are associated with this type of electronic component mounting. Through the direct attachment of the front panel of each chassis to the rack rails, vibration and impact shock imparted to the rack case or rails is directly transferred to each chassis and the sensitive electronic circuity contained therein. Similarly, vibration induced by components having moving parts is transferred to other components commonly mounted on the same rack rails.
Another problem associated with rack mounting of multiple electronic components is the transfer of electrostatic discharge from one component to another through common rack rail attachment. Similarly, radio frequency interference collected by either the components, component chassis, or the rack rails is transferred to every other component on the rack. Also, even a minor line-to-ground fault in any individual component may be communicated to each component on the same rack and cause electrical damage to circuitry which is often grounded to its chassis.
Previous attempts to insulate rack mounted electronic components from the adverse affects of vibration and impact shock include the use of a foam lined box into which the rack is inserted or, similarly, the use of foam blocks provided at key points of contact with the exterior of the chassis. This approach is not effective, however, in completely isolating the components from vibration or impact shock which ultimately reaches the rack rails, nor does this approach eliminate the problems of electrical nature which arise as a result of each component being attached directly to a common rack rail, such as electrostatic discharge from and between each component, and radio frequency interference collected by and distributed through the rack and components. Rack rails have also been suspended from a framework mounted upon rubber housings within a rack case to dampen vibration or impact shock imparted to the rack case. This approach also fails to isolate the rack mounted components from vibration and impact shock which ultimately reaches the rack rails within the case, nor does it eliminate electrostatic induction or discharge or radio frequency conductivity through or from the rack rails to each component.